Venturi burner and Carbon Monoxide

[KPeacock]

Has anyone else had a problem with carbon monoxide levels while using a venturi style burner? I have run my blown forge for hours with the doors both open and closed and never had any problems with CO. Typically, I open a window and and opposite door just to cool the air temps down a bit.

 

I just finished insulating a borge body and installed a burner yesterday and after about 20 minutes of burn time, my carbon monoxide detector was chirping like crazy. This is the first time that this alarm has sounded. I have both CO and flamable gas detectors and I like to keep both of them silent.

 

I have not done any testing to see why this particular forge is putting out CO, but I figured I'd post it and see if others have had similar experiences.

 

Thanks,

 

Kris

[Bryan Bondurant]

Kris, its one thing run a cook stove in a closed area for a short time but running a forge is another. You need exhaust for the gas and clean air coming in to refresh the oxygen for you to breath.

 

I'm pretty serious about this as we had a couple guys die close to my old place from taking a barbecue into a tent and zipping it up, strangely the dog lay close to the ground and survived but two young guys around thirty were dead. This has also happened when guys would start their cars in the garage and the exhaust went into the home as they listened to music, in one case it killed a entire family in Florida.

[Simon Attwood]

strangely the dog lay close to the ground and survived but two young guys around thirty were dead.

 

that is curious, because I always thought that carbon monoxide was heavier than air.

 

I'd never consider running a gas forge anywhere that didn't have plenty of ventilation. CO is a deadly killer primarily because, unless you have a detector, it sneaks up on you without you knowing

[Jeroen Zuiderwijk]

that is curious, because I always thought that carbon monoxide was heavier than air.

Weight doesn't matter for gasses, they mix evenly. The difference is heat, as the hot gasses hang higher then incoming colder air.

 

I'd never consider running a gas forge anywhere that didn't have plenty of ventilation. CO is a deadly killer primarily because, unless you have a detector, it sneaks up on you without you knowing

I've also read that there may be long term concequences of breathing CO (though not yet fully understood medically), potentially damaging nerves, heart etc. So just keeping levels low enough that you don't die instantly isn't good enough. So it's best to keep as much ventilation as possible, and breath as little of the fumes from the forge as possible.

[Mike Blue]

...I've also read that there may be long term concequences of breathing CO (though not yet fully understood medically), potentially damaging nerves, heart etc. So just keeping levels low enough that you don't die instantly isn't good enough. So it's best to keep as much ventilation as possible, and breath as little of the fumes from the forge as possible.

 

There is certainly no argument with keeping a supply of fresh air. CO binds irreversibly with the hemoglobin in the red blood cell. That means that cell is done carrying oxygen for you. The potential damage to organs is the hypoxia, not the CO itself. A chronic exposure to CO, like someone who is smoking cigarettes, will cause a compensatory rise in the amount of red blood cells (see hematocrit). For a while, someone young (read immortal and invincible) will compensate successfully. As the number of miles accumulates compensatory mechanism are going to wear out themselves and chronic effects will show themselves more readily.

 

Perversely, the generation of CO in a forge environment, especially someone who intends to use a reducing atmosphere to weld steels, is a requirement. So you're doing something you want and trying to balance the safety of what you want to do against the potential risks. Sounds pretty normal for a blacksmith to me.

 

Blacksmithing is an inherently dangerous avocation.

[Jeroen Zuiderwijk]

Blacksmithing is an inherently dangerous avocation.

It's only as dangerous as you make it. If you take all the necessary precautions, it doesn't have to be any more dangerous then cooking on a gas furnace in the kitchen (by someone not doing anything foolish that is ).

[dragoncutlery]

first were did you get a borge?

 

second why the insulation?

 

third shouldn't we be calling the federation on this one?

 

i for one am setting down the phazer and going for projectiles and hand weapons

 

[Simon Attwood]

first were did you get a borge?

 

second why the insulation?

 

third shouldn't we be calling the federation on this one?

 

i for one am setting down the phazer and going for projectiles and hand weapons

 

 

 

Any more from you, Brandon, and you'll get assimilated

[Matt Bower]

I work outside, so I don't have a CO detector. But when I first started using my T-Rex burner I had trouble with it running rich -- which of course produces CO. The problem was back pressure in that particular forge design. NA burners are sensitive to it (even really efficient ones like the R-Rex), and it can prevent them from drawing sufficient combustion air for a clean burn. If there's a way to let the forge exhaust a more efficiently without tearing it up, you might try that. A smaller gas orifice with higher pressure might also help.

 

That might not be the problem, but it's worth checking out.

 

This is in addition to what the others said about good ventilation.

Edited February 9, 2009 by Matt Bower

[KPeacock]

Thanks for the comments folks,

 

While still young enough be invincible....well almost still invincible...I do recognize that there are potential hazards in involved with this hobby. There is precious little one can do to take the danger out of a yellow hot piece of steel. I'm not terribly concerned about these dangers as there is nothing that can eliminate them. Safe practices work for the most part, but they can not eliminate the danger.

 

The ventilation was a major concern to me when I first began forging, but as the temperatures droped down near -30°F I was a bit more reluctant to open the doors right away. I waited for the shop to come up to temp first. The CO detector never tripped. There is something about this forge that is putting out far more CO than my blown forge.

 

I'll certainly be more cautious while operating this forge, and I'll do some more testing to see why the CO levels are rising. The forge was running for around 20 minutes before the alarm sounded. the last 5 minutes I had the pressure set at 15psi through a .045" tip in an effort to reach welding temps. I was unable to complete this test as I decided to get to fresh air.

 

Fortunately, it's a detached garage, so the potential health risks are mine, and mine alone.

 

Thanks for your thoughts,

 

Kris

[KPeacock]

first were did you get a borge?

 

second why the insulation?

 

third shouldn't we be calling the federation on this one?

 

i for one am setting down the phazer and going for projectiles and hand weapons

 

 

A "borge" is a home Built fORGE. I refer to it as a "borge" until it's functioning properly. It then becomes a "forge"

 

Either that, or these meat hooks smashed the wrong key as I was pounding on the keyboard.

[Doug Seward]

Coincidently, I discovered that my T-Rex Fired Propane tank forge puts out significant CO. It was about 35F in the shop and I fired up the forge just inside the theoretical 2 car detached garage door. The sliding garage door was open about 4-5 ft wide -- call it 30 sq ft of opening with forge about 2ft inside the door. I have a CO detector towards the back of the garage, thinking that the highest CO would be furthest from the open door. Within 10 minutes of starting the forge, the CO detector went off. I went over to check it and it displayed 161 ppm. I shut off the forge and turned on a floor fan. After 5 min or so, CO detector was still chirping indicating 105 PPM. It took another 10 minutes with the fan to make the detector happy.

 

I usually forge outside, but figured on reusing the heat. Lesson learned. I switched over to a catalytic propane heater which did not bother the CO Detector at all. -Doug

[Matt Bower]

Kris,

 

0.045" is a pretty big orifice for most forges. You don't necessarily need a big orifice to get a large volume of propane; high pressure through a small orifice can do the same thing, with the advantage that it tends to suck in more combustion air and burn cleaner. (The down side is that if you have a hose rupture at high pressure, the propane will come out out awfully fast.) A cleaner burn is also apt to be hotter. Consider trying a smaller orifice.

Edited February 10, 2009 by Matt Bower

[KPeacock]

Matt,

 

I'll try various sizes on my next runs with it. I was forced to use a .045" tip in order to get a steady flame when initially test firing the burner. I suspect that I'll get better results with it now that I have a forge to use it in. I have all sorts of variables to play with on this thing. Air baffle, tip size, pressure, also orifice location is somewhat adjustable on this burner. I'm sure it'll take a bit of playing around to get it dialed in the way it ought to be.

 

Thanks,

 

Kris